Replacing mouse balls

Replacing mouse balls
This memo is from an unnamed computer company. It went to all field engineers about a computer peripheral problem. The author of this memo was quite serious. The engineers rolled on the floor! Especially note the last sentence.
Mouse balls are now available as FRU (Field Replacement Unit).Therefore if a mouse fails to operate or should it perform erratically, it may need a ball replacement.
Because of the delicate nature of this procedure, replacement of mouse balls should only be attempted by properly trained personnel.Before proceeding, determine the type of mouse balls by examining the underside of the mouse. Domestic balls will be larger and harder than foreign balls.
Ball removal procedures differ depending upon the manufacture of the mouse.
Foreign balls can be replaced using the pop-off method. Domestic ball are replaced by using the twist-off method.Mouse balls are not usually static-sensitive. However, excessive handling can result in sudden discharge.Upon completion of ball replacement, the mouse may be used immediately.
It is recommended each replacer have a pair of spare balls for maintaining optimum customer satisfaction.
Any customer missing his balls should contact the local personnel in charge of removing and replacing these necessary items.